Discovery of the Closest Ultrastripped Supernova: SN 2021agco in UGC 3855
Preprint 2023 en
Authors
SY
Shengyu Yan
XW
Xiaofeng Wang
XG
Xing Gao
Abstract
1 min read
We present the discovery and studies of the helium-rich, fast-evolving supernova (SN) 2021agco at a distance of $\sim$ 40 Mpc. Its early-time flux is found to rise from half peak to the peak of $-16.06\pm0.42$ mag in the $r$ band within $2.4^{+1.5}_{-1.0}$ days, and the post-peak light curves also decline at a much faster pace relative to normal stripped-envelope SNe of Type Ib/Ic. The early-time spectrum of SN~2021agco ($t \approx 1.0$ days after the peak) is characterized by a featureless blue continuum superimposed with a weak emission line of ionized C III, and the subsequent spectra show prominent He I lines. Both the photometric and spectroscopic evolution shows close resemblances to SN 2019dge, which is believed to have an extremely stripped progenitor. We reproduce the multicolor light curves of SN 2021agco with a model combining shock-cooling emission with \Ni decay. The best-fit results give an ejecta mass of $\approx 0.3$~M$_\odot$ and a synthesized nickel mass of $\approx 2.2\times10^{-2}$~M$_\odot$. The progenitor is estimated to have an envelope radius $R_{\rm env} \approx 80$~R$_\odot$ and a mass $M_{\rm env} \approx 0.10$~M$_\odot$. All these suggest that SN~2021agco can be categorized as an ultrastripped SN~Ib, representing the closest object of this rare subtype. This SN is found to explode in the disk of an Sab-type galaxy with an age of $\sim 10.0$~Gyr and low star-forming activity. Compared to normal SNe Ib/c, the host galaxies of SN 2021agco and other ultrastripped SNe tend to have relatively lower metallicity, which complicates the properties of their progenitor populations.
Shengyu Yan, Xiaofeng Wang, Xing Gao, Jujia Zhang, Alexei V Filippenko, Thomas G. Brink, Jun Mo, Weili Lin, Danfeng Xiang, Xiaoran Ma, Fangzhou Guo, L. Tomasella, S. Benetti, Yongzhi Cai, E. Cappellaro, Zhihao Chen, Zhitong Li, A. Pastorello, Tianmeng Zhang
S. Bose, Subo Dong, C. S. Kochanek, M. Stritzinger, C. Ashall, S. Benetti, E. Falco, Alexei V Filippenko, A. Pastorello, J. L. Prieto, A. Somero, Tuguldur Sukhbold, M. Zhang, Katie Auchettl, Thomas G. Brink, J. S. Brown, Ping Chen, A. Fiore, D. Grupe, T. W. S. Holoien, Peter Lundqvist, S. Mattila, R. L. Mutel, D. Pooley, R. S. Post,
Yize Dong, S. Valenti, C. Ashall, Marc Williamson, David J. Sand, Schuyler D. Van Dyk, Saurabh W. Jha, M. Lundquist, M. Modjaz, Jennifer E. Andrews, J. Jencson, G. Hosseinzadeh, Jeniveve Pearson, Lindsey A. Kwok, Teresa Boland, E. Y. Hsiao, Nathan Smith, N. Elias–Rosa, Shubham Srivastav, S. J. Smartt, M. Fulton, WeiKang Zheng, Thomas G. Brink, ,
Gaobo Xi, Xiaofeng Wang, Wenxiong Li, Jun Mo, Jujia Zhang, Jialian Liu, Zhihao Chen, Alexei V Filippenko, WeiKang Zheng, Thomas G. Brink, Xinghan Zhang, Hanna Sai, Shuhrat Ehgamberdiev, D. O. Mirzaqulov, Jicheng Zhang
Han Lin, Xiaofeng Wang, Jujia Zhang, Weili Lin, Jun Mo, Alexei V Filippenko, WeiKang Zheng, P. J. Brown, Danfeng Xiang, Fang Huang, Yongzhi Cai, Tianmeng Zhang, Xue Li, Liming Rui, Xinghan Zhang, Hanna Sai, Xulin Zhao, M. L. Graham, I. Shivvers, G. Halevi, H. Yuk, Thomas G. Brink
Discussion(0)
No comments yet. Be the first to comment.